(possible spoiler, but its pretty obvious within the first 2 mins of the movie)
When Jin-seok Lee got the phone call from the military at the beginning of the movie, he was told that it was the body of Jin-seok Lee and he was like "no i'm Jin-Seok Lee, could it have been my brother?". But it is actually the body of his brother, Jin-tae Lee. How did they made this mistake and why? Is there something I am missing?
The extrication team used photographs and personal stuff which has been found nearby the remains to identify the soldiers. I think, the name of Jin-Seok had been engraved on the pen (a present of Jin-tae) wich he left with his brother at the final war scene.
shareI also thought that Jin-tae would be erased from South Korean military records because he defected, that's why the team couldn't find him.
"Night, night! Keep your butthole tight!" Tron- The Chappelle's Show
That's correct.Jin-tae defected to North Korea that is why his records from the South Korea Military were deleted.